diff options
Diffstat (limited to 'drivers/gpu/drm/drm_dp_dual_mode_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_dp_dual_mode_helper.c | 524 |
1 files changed, 524 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_dp_dual_mode_helper.c b/drivers/gpu/drm/drm_dp_dual_mode_helper.c new file mode 100644 index 000000000..e7f4fe284 --- /dev/null +++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c @@ -0,0 +1,524 @@ +/* + * Copyright © 2016 Intel Corporation + * + * Permission is hereby granted, free of charge, to any person obtaining a + * copy of this software and associated documentation files (the "Software"), + * to deal in the Software without restriction, including without limitation + * the rights to use, copy, modify, merge, publish, distribute, sublicense, + * and/or sell copies of the Software, and to permit persons to whom the + * Software is furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR + * OTHER DEALINGS IN THE SOFTWARE. + */ + +#include <linux/errno.h> +#include <linux/export.h> +#include <linux/i2c.h> +#include <linux/slab.h> +#include <linux/string.h> +#include <drm/drm_dp_dual_mode_helper.h> +#include <drm/drmP.h> + +/** + * DOC: dp dual mode helpers + * + * Helper functions to deal with DP dual mode (aka. DP++) adaptors. + * + * Type 1: + * Adaptor registers (if any) and the sink DDC bus may be accessed via I2C. + * + * Type 2: + * Adaptor registers and sink DDC bus can be accessed either via I2C or + * I2C-over-AUX. Source devices may choose to implement either of these + * access methods. + */ + +#define DP_DUAL_MODE_SLAVE_ADDRESS 0x40 + +/** + * drm_dp_dual_mode_read - Read from the DP dual mode adaptor register(s) + * @adapter: I2C adapter for the DDC bus + * @offset: register offset + * @buffer: buffer for return data + * @size: sizo of the buffer + * + * Reads @size bytes from the DP dual mode adaptor registers + * starting at @offset. + * + * Returns: + * 0 on success, negative error code on failure + */ +ssize_t drm_dp_dual_mode_read(struct i2c_adapter *adapter, + u8 offset, void *buffer, size_t size) +{ + struct i2c_msg msgs[] = { + { + .addr = DP_DUAL_MODE_SLAVE_ADDRESS, + .flags = 0, + .len = 1, + .buf = &offset, + }, + { + .addr = DP_DUAL_MODE_SLAVE_ADDRESS, + .flags = I2C_M_RD, + .len = size, + .buf = buffer, + }, + }; + int ret; + + ret = i2c_transfer(adapter, msgs, ARRAY_SIZE(msgs)); + if (ret < 0) + return ret; + if (ret != ARRAY_SIZE(msgs)) + return -EPROTO; + + return 0; +} +EXPORT_SYMBOL(drm_dp_dual_mode_read); + +/** + * drm_dp_dual_mode_write - Write to the DP dual mode adaptor register(s) + * @adapter: I2C adapter for the DDC bus + * @offset: register offset + * @buffer: buffer for write data + * @size: sizo of the buffer + * + * Writes @size bytes to the DP dual mode adaptor registers + * starting at @offset. + * + * Returns: + * 0 on success, negative error code on failure + */ +ssize_t drm_dp_dual_mode_write(struct i2c_adapter *adapter, + u8 offset, const void *buffer, size_t size) +{ + struct i2c_msg msg = { + .addr = DP_DUAL_MODE_SLAVE_ADDRESS, + .flags = 0, + .len = 1 + size, + .buf = NULL, + }; + void *data; + int ret; + + data = kmalloc(msg.len, GFP_KERNEL); + if (!data) + return -ENOMEM; + + msg.buf = data; + + memcpy(data, &offset, 1); + memcpy(data + 1, buffer, size); + + ret = i2c_transfer(adapter, &msg, 1); + + kfree(data); + + if (ret < 0) + return ret; + if (ret != 1) + return -EPROTO; + + return 0; +} +EXPORT_SYMBOL(drm_dp_dual_mode_write); + +static bool is_hdmi_adaptor(const char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN]) +{ + static const char dp_dual_mode_hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN] = + "DP-HDMI ADAPTOR\x04"; + + return memcmp(hdmi_id, dp_dual_mode_hdmi_id, + sizeof(dp_dual_mode_hdmi_id)) == 0; +} + +static bool is_type1_adaptor(uint8_t adaptor_id) +{ + return adaptor_id == 0 || adaptor_id == 0xff; +} + +static bool is_type2_adaptor(uint8_t adaptor_id) +{ + return adaptor_id == (DP_DUAL_MODE_TYPE_TYPE2 | + DP_DUAL_MODE_REV_TYPE2); +} + +static bool is_lspcon_adaptor(const char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN], + const uint8_t adaptor_id) +{ + return is_hdmi_adaptor(hdmi_id) && + (adaptor_id == (DP_DUAL_MODE_TYPE_TYPE2 | + DP_DUAL_MODE_TYPE_HAS_DPCD)); +} + +/** + * drm_dp_dual_mode_detect - Identify the DP dual mode adaptor + * @adapter: I2C adapter for the DDC bus + * + * Attempt to identify the type of the DP dual mode adaptor used. + * + * Note that when the answer is @DRM_DP_DUAL_MODE_UNKNOWN it's not + * certain whether we're dealing with a native HDMI port or + * a type 1 DVI dual mode adaptor. The driver will have to use + * some other hardware/driver specific mechanism to make that + * distinction. + * + * Returns: + * The type of the DP dual mode adaptor used + */ +enum drm_dp_dual_mode_type drm_dp_dual_mode_detect(struct i2c_adapter *adapter) +{ + char hdmi_id[DP_DUAL_MODE_HDMI_ID_LEN] = {}; + uint8_t adaptor_id = 0x00; + ssize_t ret; + + /* + * Let's see if the adaptor is there the by reading the + * HDMI ID registers. + * + * Note that type 1 DVI adaptors are not required to implemnt + * any registers, and that presents a problem for detection. + * If the i2c transfer is nacked, we may or may not be dealing + * with a type 1 DVI adaptor. Some other mechanism of detecting + * the presence of the adaptor is required. One way would be + * to check the state of the CONFIG1 pin, Another method would + * simply require the driver to know whether the port is a DP++ + * port or a native HDMI port. Both of these methods are entirely + * hardware/driver specific so we can't deal with them here. + */ + ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_HDMI_ID, + hdmi_id, sizeof(hdmi_id)); + DRM_DEBUG_KMS("DP dual mode HDMI ID: %*pE (err %zd)\n", + ret ? 0 : (int)sizeof(hdmi_id), hdmi_id, ret); + if (ret) + return DRM_DP_DUAL_MODE_UNKNOWN; + + /* + * Sigh. Some (maybe all?) type 1 adaptors are broken and ack + * the offset but ignore it, and instead they just always return + * data from the start of the HDMI ID buffer. So for a broken + * type 1 HDMI adaptor a single byte read will always give us + * 0x44, and for a type 1 DVI adaptor it should give 0x00 + * (assuming it implements any registers). Fortunately neither + * of those values will match the type 2 signature of the + * DP_DUAL_MODE_ADAPTOR_ID register so we can proceed with + * the type 2 adaptor detection safely even in the presence + * of broken type 1 adaptors. + */ + ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_ADAPTOR_ID, + &adaptor_id, sizeof(adaptor_id)); + DRM_DEBUG_KMS("DP dual mode adaptor ID: %02x (err %zd)\n", + adaptor_id, ret); + if (ret == 0) { + if (is_lspcon_adaptor(hdmi_id, adaptor_id)) + return DRM_DP_DUAL_MODE_LSPCON; + if (is_type2_adaptor(adaptor_id)) { + if (is_hdmi_adaptor(hdmi_id)) + return DRM_DP_DUAL_MODE_TYPE2_HDMI; + else + return DRM_DP_DUAL_MODE_TYPE2_DVI; + } + /* + * If neither a proper type 1 ID nor a broken type 1 adaptor + * as described above, assume type 1, but let the user know + * that we may have misdetected the type. + */ + if (!is_type1_adaptor(adaptor_id) && adaptor_id != hdmi_id[0]) + DRM_ERROR("Unexpected DP dual mode adaptor ID %02x\n", + adaptor_id); + + } + + if (is_hdmi_adaptor(hdmi_id)) + return DRM_DP_DUAL_MODE_TYPE1_HDMI; + else + return DRM_DP_DUAL_MODE_TYPE1_DVI; +} +EXPORT_SYMBOL(drm_dp_dual_mode_detect); + +/** + * drm_dp_dual_mode_max_tmds_clock - Max TMDS clock for DP dual mode adaptor + * @type: DP dual mode adaptor type + * @adapter: I2C adapter for the DDC bus + * + * Determine the max TMDS clock the adaptor supports based on the + * type of the dual mode adaptor and the DP_DUAL_MODE_MAX_TMDS_CLOCK + * register (on type2 adaptors). As some type 1 adaptors have + * problems with registers (see comments in drm_dp_dual_mode_detect()) + * we don't read the register on those, instead we simply assume + * a 165 MHz limit based on the specification. + * + * Returns: + * Maximum supported TMDS clock rate for the DP dual mode adaptor in kHz. + */ +int drm_dp_dual_mode_max_tmds_clock(enum drm_dp_dual_mode_type type, + struct i2c_adapter *adapter) +{ + uint8_t max_tmds_clock; + ssize_t ret; + + /* native HDMI so no limit */ + if (type == DRM_DP_DUAL_MODE_NONE) + return 0; + + /* + * Type 1 adaptors are limited to 165MHz + * Type 2 adaptors can tells us their limit + */ + if (type < DRM_DP_DUAL_MODE_TYPE2_DVI) + return 165000; + + ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_MAX_TMDS_CLOCK, + &max_tmds_clock, sizeof(max_tmds_clock)); + if (ret || max_tmds_clock == 0x00 || max_tmds_clock == 0xff) { + DRM_DEBUG_KMS("Failed to query max TMDS clock\n"); + return 165000; + } + + return max_tmds_clock * 5000 / 2; +} +EXPORT_SYMBOL(drm_dp_dual_mode_max_tmds_clock); + +/** + * drm_dp_dual_mode_get_tmds_output - Get the state of the TMDS output buffers in the DP dual mode adaptor + * @type: DP dual mode adaptor type + * @adapter: I2C adapter for the DDC bus + * @enabled: current state of the TMDS output buffers + * + * Get the state of the TMDS output buffers in the adaptor. For + * type2 adaptors this is queried from the DP_DUAL_MODE_TMDS_OEN + * register. As some type 1 adaptors have problems with registers + * (see comments in drm_dp_dual_mode_detect()) we don't read the + * register on those, instead we simply assume that the buffers + * are always enabled. + * + * Returns: + * 0 on success, negative error code on failure + */ +int drm_dp_dual_mode_get_tmds_output(enum drm_dp_dual_mode_type type, + struct i2c_adapter *adapter, + bool *enabled) +{ + uint8_t tmds_oen; + ssize_t ret; + + if (type < DRM_DP_DUAL_MODE_TYPE2_DVI) { + *enabled = true; + return 0; + } + + ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_TMDS_OEN, + &tmds_oen, sizeof(tmds_oen)); + if (ret) { + DRM_DEBUG_KMS("Failed to query state of TMDS output buffers\n"); + return ret; + } + + *enabled = !(tmds_oen & DP_DUAL_MODE_TMDS_DISABLE); + + return 0; +} +EXPORT_SYMBOL(drm_dp_dual_mode_get_tmds_output); + +/** + * drm_dp_dual_mode_set_tmds_output - Enable/disable TMDS output buffers in the DP dual mode adaptor + * @type: DP dual mode adaptor type + * @adapter: I2C adapter for the DDC bus + * @enable: enable (as opposed to disable) the TMDS output buffers + * + * Set the state of the TMDS output buffers in the adaptor. For + * type2 this is set via the DP_DUAL_MODE_TMDS_OEN register. As + * some type 1 adaptors have problems with registers (see comments + * in drm_dp_dual_mode_detect()) we avoid touching the register, + * making this function a no-op on type 1 adaptors. + * + * Returns: + * 0 on success, negative error code on failure + */ +int drm_dp_dual_mode_set_tmds_output(enum drm_dp_dual_mode_type type, + struct i2c_adapter *adapter, bool enable) +{ + uint8_t tmds_oen = enable ? 0 : DP_DUAL_MODE_TMDS_DISABLE; + ssize_t ret; + int retry; + + if (type < DRM_DP_DUAL_MODE_TYPE2_DVI) + return 0; + + /* + * LSPCON adapters in low-power state may ignore the first write, so + * read back and verify the written value a few times. + */ + for (retry = 0; retry < 3; retry++) { + uint8_t tmp; + + ret = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_TMDS_OEN, + &tmds_oen, sizeof(tmds_oen)); + if (ret) { + DRM_DEBUG_KMS("Failed to %s TMDS output buffers (%d attempts)\n", + enable ? "enable" : "disable", + retry + 1); + return ret; + } + + ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_TMDS_OEN, + &tmp, sizeof(tmp)); + if (ret) { + DRM_DEBUG_KMS("I2C read failed during TMDS output buffer %s (%d attempts)\n", + enable ? "enabling" : "disabling", + retry + 1); + return ret; + } + + if (tmp == tmds_oen) + return 0; + } + + DRM_DEBUG_KMS("I2C write value mismatch during TMDS output buffer %s\n", + enable ? "enabling" : "disabling"); + + return -EIO; +} +EXPORT_SYMBOL(drm_dp_dual_mode_set_tmds_output); + +/** + * drm_dp_get_dual_mode_type_name - Get the name of the DP dual mode adaptor type as a string + * @type: DP dual mode adaptor type + * + * Returns: + * String representation of the DP dual mode adaptor type + */ +const char *drm_dp_get_dual_mode_type_name(enum drm_dp_dual_mode_type type) +{ + switch (type) { + case DRM_DP_DUAL_MODE_NONE: + return "none"; + case DRM_DP_DUAL_MODE_TYPE1_DVI: + return "type 1 DVI"; + case DRM_DP_DUAL_MODE_TYPE1_HDMI: + return "type 1 HDMI"; + case DRM_DP_DUAL_MODE_TYPE2_DVI: + return "type 2 DVI"; + case DRM_DP_DUAL_MODE_TYPE2_HDMI: + return "type 2 HDMI"; + case DRM_DP_DUAL_MODE_LSPCON: + return "lspcon"; + default: + WARN_ON(type != DRM_DP_DUAL_MODE_UNKNOWN); + return "unknown"; + } +} +EXPORT_SYMBOL(drm_dp_get_dual_mode_type_name); + +/** + * drm_lspcon_get_mode: Get LSPCON's current mode of operation by + * reading offset (0x80, 0x41) + * @adapter: I2C-over-aux adapter + * @mode: current lspcon mode of operation output variable + * + * Returns: + * 0 on success, sets the current_mode value to appropriate mode + * -error on failure + */ +int drm_lspcon_get_mode(struct i2c_adapter *adapter, + enum drm_lspcon_mode *mode) +{ + u8 data; + int ret = 0; + int retry; + + if (!mode) { + DRM_ERROR("NULL input\n"); + return -EINVAL; + } + + /* Read Status: i2c over aux */ + for (retry = 0; retry < 6; retry++) { + if (retry) + usleep_range(500, 1000); + + ret = drm_dp_dual_mode_read(adapter, + DP_DUAL_MODE_LSPCON_CURRENT_MODE, + &data, sizeof(data)); + if (!ret) + break; + } + + if (ret < 0) { + DRM_DEBUG_KMS("LSPCON read(0x80, 0x41) failed\n"); + return -EFAULT; + } + + if (data & DP_DUAL_MODE_LSPCON_MODE_PCON) + *mode = DRM_LSPCON_MODE_PCON; + else + *mode = DRM_LSPCON_MODE_LS; + return 0; +} +EXPORT_SYMBOL(drm_lspcon_get_mode); + +/** + * drm_lspcon_set_mode: Change LSPCON's mode of operation by + * writing offset (0x80, 0x40) + * @adapter: I2C-over-aux adapter + * @mode: required mode of operation + * + * Returns: + * 0 on success, -error on failure/timeout + */ +int drm_lspcon_set_mode(struct i2c_adapter *adapter, + enum drm_lspcon_mode mode) +{ + u8 data = 0; + int ret; + int time_out = 200; + enum drm_lspcon_mode current_mode; + + if (mode == DRM_LSPCON_MODE_PCON) + data = DP_DUAL_MODE_LSPCON_MODE_PCON; + + /* Change mode */ + ret = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_LSPCON_MODE_CHANGE, + &data, sizeof(data)); + if (ret < 0) { + DRM_ERROR("LSPCON mode change failed\n"); + return ret; + } + + /* + * Confirm mode change by reading the status bit. + * Sometimes, it takes a while to change the mode, + * so wait and retry until time out or done. + */ + do { + ret = drm_lspcon_get_mode(adapter, ¤t_mode); + if (ret) { + DRM_ERROR("can't confirm LSPCON mode change\n"); + return ret; + } else { + if (current_mode != mode) { + msleep(10); + time_out -= 10; + } else { + DRM_DEBUG_KMS("LSPCON mode changed to %s\n", + mode == DRM_LSPCON_MODE_LS ? + "LS" : "PCON"); + return 0; + } + } + } while (time_out); + + DRM_ERROR("LSPCON mode change timed out\n"); + return -ETIMEDOUT; +} +EXPORT_SYMBOL(drm_lspcon_set_mode); |